1. Field of the Invention
The present invention relates to a receiver of a super-heterodyne system.
2. Description of Related Art
In a receiver of a super-heterodyne system, the reception characteristics such as a reception sensitivity and image interference characteristics are degraded if the rated frequency relation between a reception frequency, a local oscillation frequency and an intermediate frequency is shifted.
A test signal generator is therefore provided for checking and adjusting the reception sensitivity, the center frequencies of an antenna tuning circuit and an intermediate frequency filter, and the reception characteristics such as image interference characteristics. A receiver is known which has therein a test signal generator of this type to provide a self test function. As prior art documents, refer to, for example, Japanese Laid-open Patent Applications No. 2000-13336 and No. 2001 -119316.